/// <summary>Returns an existing reference to the UI used for the drop-down (or creates a new one)</summary>
/// <param name="attachedTo">Object the UI is to be attached to</param>
/// <returns>UI element</returns>
private static AutoComplete GetAutoCompleteUIElement(UIElement attachedTo)
{
var dropDownUI = GetAutoCompleteUI(attachedTo);
if (dropDownUI == null)
{
dropDownUI = new AutoComplete();
attachedTo.GotFocus += (sender, e) =>
{
var adornerLayer = AdornerLayer.GetAdornerLayer(attachedTo);
if (adornerLayer == null)
{
return;
}
var currentAdorners = adornerLayer.GetAdorners(attachedTo);
var adornerFound = false;
if (currentAdorners != null)
{
if (currentAdorners.OfType <AutoCompleteDropDownAdorner>().Any())
{
adornerFound = true;
}
}
if (dropDownUI._adornerLoaded && adornerFound)
{
return;
}
var parent = VisualTreeHelper.GetParent(dropDownUI);
if (parent != null)
{
if (parent is AutoCompleteDropDownAdorner oldAdorner)
{
oldAdorner.DisconnectVisualChild(dropDownUI);
}
}
var adorner = new AutoCompleteDropDownAdorner(attachedTo, dropDownUI);
var localAdorner = adorner;
adornerLayer.Add(adorner);
dropDownUI._adornerLoaded = true;
if (dropDownUI.Items.Count > 0)
{
dropDownUI.Visibility = Visibility.Visible;
}
localAdorner.InvalidateMeasure();
localAdorner.InvalidateArrange();
};
attachedTo.PreviewKeyDown += (sender, e) =>
{
switch (e.Key)
{
case Key.Up:
case Key.Down:
{
var index = dropDownUI.SelectedIndex;
switch (e.Key)
{
case Key.Down:
index++;
if (index >= dropDownUI.Items.Count)
{
index = dropDownUI.Items.Count - 1;
}
break;
case Key.Up:
index--;
if (index < 0)
{
index = 0;
}
break;
}
dropDownUI.SelectedIndex = index;
dropDownUI.ScrollIntoView(dropDownUI.SelectedItem);
e.Handled = true;
}
break;
case Key.Enter:
{
if (dropDownUI.SelectedIndex > -1)
{
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
}
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
attachedTo.Focus();
var text = attachedTo as TextBox;
if (text != null)
{
text.SelectionStart = text.Text.Length;
}
}
break;
}
};
attachedTo.KeyUp += (sender, e) =>
{
if (e.Key != Key.Enter && dropDownUI.Visibility == Visibility.Collapsed)
{
if (dropDownUI.Items.Count > 0)
{
dropDownUI.Visibility = Visibility.Visible;
}
else
{
dropDownUI._uiEligibleToBeVisible = true;
}
}
if (dropDownUI.Visibility == Visibility.Visible && dropDownUI.Items.Count == 0)
{
dropDownUI.Visibility = Visibility.Collapsed;
}
};
dropDownUI.PreviewKeyDown += (sender, e) =>
{
if (e.Key != Key.Enter)
{
return;
}
if (dropDownUI.SelectedIndex > -1)
{
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
}
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
};
dropDownUI.MouseLeftButtonUp += (sender, e) =>
{
if (dropDownUI.SelectedIndex <= -1)
{
return;
}
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
e.Handled = true;
attachedTo.Focus();
var text = attachedTo as TextBox;
if (text != null)
{
text.SelectionStart = text.Text.Length;
}
};
attachedTo.LostFocus += (sender, e) =>
{
if (!dropDownUI.IsKeyboardFocusWithin && !attachedTo.IsKeyboardFocusWithin)
{
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
}
};
dropDownUI.LostFocus += (sender, e) =>
{
if (!dropDownUI.IsKeyboardFocusWithin && !attachedTo.IsKeyboardFocusWithin)
{
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
}
};
SetAutoCompleteUI(attachedTo, dropDownUI);
}
return(dropDownUI);
}
/// <summary>Constructor</summary>
/// <param name="adornedElement">Adorned element (typically a textbox)</param>
/// <param name="ui">The UI that is to be used in the drop-down</param>
public AutoCompleteDropDownAdorner(UIElement adornedElement, AutoComplete ui)
: base(adornedElement)
{
_ui = ui;
AddVisualChild(ui);
}
/// <summary> /// Disconnects a visual child element /// </summary> /// <param name="ui"></param> public void DisconnectVisualChild(AutoComplete ui) => RemoveVisualChild(ui);
/// <summary>Auto complete UI</summary> /// <param name="obj">Object to set the auto complete UI on</param> /// <param name="value">Value to set</param> public static void SetAutoCompleteUI(DependencyObject obj, AutoComplete value) => obj.SetValue(AutoCompleteUIProperty, value);
/// <summary>
/// Disconnects a visual child element
/// </summary>
/// <param name="ui"></param>
public void DisconnectVisualChild(AutoComplete ui)
{
RemoveVisualChild(ui);
}
/// <summary>Constructor</summary>
/// <param name="adornedElement">Adorned element (typically a textbox)</param>
/// <param name="ui">The UI that is to be used in the drop-down</param>
public AutoCompleteDropDownAdorner(UIElement adornedElement, AutoComplete ui)
: base(adornedElement)
{
_ui = ui;
AddVisualChild(ui);
}
/// <summary>Returns an existing reference to the UI used for the drop-down (or creates a new one)</summary>
/// <param name="attachedTo">Object the UI is to be attached to</param>
/// <returns>UI element</returns>
private static AutoComplete GetAutoCompleteUIElement(UIElement attachedTo)
{
var dropDownUI = GetAutoCompleteUI(attachedTo);
if (dropDownUI == null)
{
dropDownUI = new AutoComplete();
attachedTo.GotFocus += (sender, e) =>
{
var adornerLayer = AdornerLayer.GetAdornerLayer(attachedTo);
if (adornerLayer == null) return;
var currentAdorners = adornerLayer.GetAdorners(attachedTo);
var adornerFound = false;
if (currentAdorners != null)
if (currentAdorners.OfType<AutoCompleteDropDownAdorner>().Any())
adornerFound = true;
if (dropDownUI._adornerLoaded && adornerFound) return;
var parent = VisualTreeHelper.GetParent(dropDownUI);
if (parent != null)
{
var oldAdorner = parent as AutoCompleteDropDownAdorner;
if (oldAdorner != null)
oldAdorner.DisconnectVisualChild(dropDownUI);
}
var adorner = new AutoCompleteDropDownAdorner(attachedTo, dropDownUI);
var localAdorner = adorner;
adornerLayer.Add(adorner);
dropDownUI._adornerLoaded = true;
if (dropDownUI.Items.Count > 0) dropDownUI.Visibility = Visibility.Visible;
localAdorner.InvalidateMeasure();
localAdorner.InvalidateArrange();
};
attachedTo.PreviewKeyDown += (sender, e) =>
{
switch (e.Key)
{
case Key.Up:
case Key.Down:
{
var index = dropDownUI.SelectedIndex;
switch (e.Key)
{
case Key.Down:
index++;
if (index >= dropDownUI.Items.Count)
index = dropDownUI.Items.Count - 1;
break;
case Key.Up:
index--;
if (index < 0)
index = 0;
break;
}
dropDownUI.SelectedIndex = index;
dropDownUI.ScrollIntoView(dropDownUI.SelectedItem);
e.Handled = true;
}
break;
case Key.Enter:
{
if (dropDownUI.SelectedIndex > -1)
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
attachedTo.Focus();
var text = attachedTo as TextBox;
if (text != null)
text.SelectionStart = text.Text.Length;
}
break;
}
};
attachedTo.KeyUp += (sender, e) =>
{
if (e.Key != Key.Enter && dropDownUI.Visibility == Visibility.Collapsed)
if (dropDownUI.Items.Count > 0)
dropDownUI.Visibility = Visibility.Visible;
else
dropDownUI._uiEligibleToBeVisible = true;
if (dropDownUI.Visibility == Visibility.Visible && dropDownUI.Items.Count == 0) dropDownUI.Visibility = Visibility.Collapsed;
};
dropDownUI.PreviewKeyDown += (sender, e) =>
{
if (e.Key != Key.Enter) return;
if (dropDownUI.SelectedIndex > -1)
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
};
dropDownUI.MouseLeftButtonUp += (sender, e) =>
{
if (dropDownUI.SelectedIndex <= -1) return;
SetAutoCompleteSelectedItem(attachedTo, dropDownUI.SelectedItem);
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
e.Handled = true;
attachedTo.Focus();
var text = attachedTo as TextBox;
if (text != null)
text.SelectionStart = text.Text.Length;
};
attachedTo.LostFocus += (sender, e) =>
{
if (!dropDownUI.IsKeyboardFocusWithin && !attachedTo.IsKeyboardFocusWithin)
{
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
}
};
dropDownUI.LostFocus += (sender, e) =>
{
if (!dropDownUI.IsKeyboardFocusWithin && !attachedTo.IsKeyboardFocusWithin)
{
dropDownUI.Visibility = Visibility.Collapsed;
dropDownUI._uiEligibleToBeVisible = false;
}
};
SetAutoCompleteUI(attachedTo, dropDownUI);
}
return dropDownUI;
}
/// <summary>Auto complete UI</summary>
/// <param name="obj">Object to set the auto complete UI on</param>
/// <param name="value">Value to set</param>
public static void SetAutoCompleteUI(DependencyObject obj, AutoComplete value)
{
obj.SetValue(AutoCompleteUIProperty, value);
}
